bbm - That's an interesting thought/possibility.
In terms of everything LE is saying publicly about MR, *if* he is their POI, I highly doubt they would say anything to let on he is in fact their focus. I would imagine if he is in their sights they would try to keep him calm and cooperating, unaware of how much they have on him.
Either way MR knows the truth, it's just a matter of him knowing what LE knows or doesn't know.
LE isn't going to say they found something significant while executing the search warrant, but as you suggested with the itemized receipt - if there was something he didn't get back, he could figure things out.
IMO it's highly plausible that what LE is saying publicly (and what they AREN'T saying/doing publicly) may be to create a false sense of security for MR *if* they think he's involved, as they are more than happy to have his continued cooperation and hope it will continue until there are answers.